I mean you can configure RPi4 as HQP OS’s “UAC2 input” for your PC/Mac or iOS devices.
RPi4’s USB type-C connector is not only for power supply but also can be the USB input:
- add
dtoverlay=dwc2
in theconfig.txt
- add this line to
hqplayerd.xml
<input channels="2" device="UAC2" format="auto" name="UAC2" pack_sdm="1" period_time="100" type="uac2">
If you want to use this trick for iOS devices, please use powered USB hub. RPi4 still need 5V to boot. Photo shows iPhone → iFi iUSB3 → RPi4 → iFi DAC for AM or other music player upsampling.